Mulberry leaves is the main food of silkworm. Silk production is dependent on nutritive value of mulberry leaves. The purpose of this investigation is studying the impact of prebiotic agents on nutrition and silk production of silkworm. So to explore the effect of Helianthus tuberosus (Jerusalem artichoke) as a source of inulin on the activity of some probiotic bacteria (Lactobacillus rhamnosus and Bifidobacterium bifidum)that added to mulberry leaves which offered to silkworm Bombyx mori L.. Mulberry leaves was fortified with prebiotic agent with two different concentrations (3%&6%) and offered 4 times day after day from 4^th instar till cocooning. Results revealed that there is no a significant variance between 3% and 6% in all treatments under studied while using mixture of the two probioticimproved larval performance which recorded height value in consumed food, Assimilation, Tissue growth, nutritional parameters in 4^th and 5^th instars and recorded, the highest values in economic parameters, silk (length, weight and size in the two used concentrations compared with control.